X-Y Positions input device for display system

ABSTRACT

An X-Y input device comprises a rotatable ball, a first driven roller held in contact with the rotatable ball and rotatable in response to rotation of the rotatable ball, a second driven roller held in contact with the rotatable ball and rotatable in response to rotation of the rotatable ball, the second driven roller having an axis of rotation extending substantially perpendicularly to that of the first driven roller, first rotation detector means for detecting an amount of rotation of the first driven roller, and second rotation detector means for detecting an amount of rotation of the second driven roller. Each of the rotation detector means comprises a pattern base plate including a central pattern and a peripheral pattern concentric with the central pattern, a slider having a first contact end held in slidable contact with the central pattern and a second contact end held in slidable contact with the peripheral pattern, and a slider support supporting the slider and connected to each of the driven rollers for rotation. The first contact end of the slider is held in contact with the central pattern at a point aligned with a central axis of rotation of the driven roller, or the central pattern of the pattern base plate has a center aligned with a central axis of rotation of the driven roller.

BACKGROUND OF THE INVENTION

The present invention relates to an X-Y input device, and moreparticularly to an X-Y input device suitable for use as a graphics inputdevice associated with a graphic display apparatus.

Graphic display apparatus are basically composed of a display screen, adisplay controller, a data channel, and an input device which may be ofvarious types. One known input device is a "joystick" having a leversupported by a gimbal mechanism and tiltable by the operator in anydirection. A control device detects the direction and angle of tilt ofthe lever and generates voltages or digital signals indicative ofcoordinate values in X and Y directions. This type of input device isdisadvantageous however in that the range of angular movement of thelever is limited and data signals entered by the operator are relativelyunstable.

In an effort to eliminate the above shortcomings, there has in recentyears been developed an input device device called a "mouse". One typeof the mouse has a rotatable member such as a steel ball (hereinafterreferred to as a "ball"), a first driven roller held in contact with theball and rotatable in response to rotation thereof, and a second drivenroller held in contact with the ball and rotatable in response torotation thereof. The first and second rollers have their axes ofrotation extending substantially perpendicularly to each other. Themouse also includes first and second angle detector means composed ofvariable resistors and encoders for separately detecting angles ofrotation of the first and second driven rollers. The ball, first andsecond driven rollers, and first and second angle detector means are allhoused in a casing.

The casing has an opening defined in its bottom with the ball partlyprojecting through the opening. In use, the casing is held by theoperator to place the ball against a given base or surface. By movingthe case to cause the ball to roll on the surface in any desiredtwo-dimensional directions, the first and second driven rollers arerotated about their own axes in directions and through angles dependenton the rolling movement of the ball. The directions and angles ofrotation of the driven rollers are converted by the first and secondangle detector means into voltages or digital signals representative ofcoordinate values in X and Y directions. The generated signals are thenentered into a display apparatus.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an X-Y input deviceof the type known as a mouse, which is highly reliable in constructionand operation.

According to the present invention, there is provided an X-Y inputdevice comprising a rotatable ball, a first driven roller held incontact with the rotatable ball and rotatable in response to rotation ofthe rotatable ball, a second driven roller held in contact with therotatable ball and rotatable in response to rotation of the rotatableball, the second driven roller having an axis of rotation extendingsubstantially perpendicularly to that of the first driven roller, firstrotation detector means for detecting an amount of rotation of the firstdriven roller, and second rotation detector means for detecting anamount of rotation of the second driven roller, each of the rotationdetector means comprising a pattern base plate including a centralpattern and a peripheral pattern concentric with the central pattern, aslider having a first contact end held in slidable contact with thecentral pattern and a second contact end held in slidable contact withthe peripheral pattern, and a slider support supporting the slider andconnected to each of the driven rollers for rotation therewith, thefirst contact end of the slider being held in contact with the centralpattern at a point aligned with a central axis of rotation of the drivenroller, or the central pattern of the pattern base plate having a centeraligned with a central axis of rotation of the driven roller.

Since the point of contact between the first contact end and the centralpattern is aligned with the central axis of rotation of the drivenroller, resistance to the rotation of the driven roller due to contactbetween the first contact end and the central pattern is minimized. Theslider support is directly connected to the driven roller and hencerequires no rotatable shaft. This can reduce the number of parts used,and the input device can be of a low cost and small in size. The factthat the center of the central pattern is aligned with the central axisof rotation of the driven roller and the slider support is directlycoupled to the driven roller allows the slider and the driven roller tobe centered easily relatively to each other. As a result, the drivenroller, the slider, and the pattern base plate can properly bepositioned with respect to each other. Accordingly, the condition ofrotation of the ball can accurately be detected through the drivenrollers for highly reliable operation.

The above and other objects, features and advantages of the presentinvention will become more apparent from the following description whentaken in conjunction with the accompanying drawings in which preferredembodiments of the present invention are shown by way of illustrativeexample.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a graphic display apparatus including anX-Y input device according to the present invention;

FIG. 2 is a plan view of the X-Y input device;

FIG. 3 is a front elevational view of the input device;

FIG. 4 is a bottom view of the input device;

FIG. 5 is a side elevational view of the input device;

FIG. 6 is a plan view of a lower case of the input device;

FIG. 7 is a cross-sectional view taken along line A--A of FIG. 6;

FIG. 8 is a cross-sectional view taken along line B--B of FIG. 6;

FIG. 9 is a cross-sectional view taken along line C--C of FIG. 6;

FIG. 10 is a cross-sectional view taken along line D--D of FIG. 6;

FIG. 11 is a cross-sectional view taken along line E--E of FIG. 6;

FIG. 12 is a cross-sectional view taken along line F--F of FIG. 6;

FIG. 13 is a plan view of a ring-shaped cover;

FIG. 14 is a front elevational view of the ring-shaped cover;

FIG. 15 is a bottom view of the ring-shaped cover;

FIG. 16 is a cross-sectional view of the ring-shaped cover;

FIG. 17 is a cross-sectional view of the ring-shaped cover as attachedin position;

FIGS. 18 and 19 are fragmentary cross-sectional views of a support balland a support leg as they are assembled;

FIG. 20 is plan view of an annular holder;

FIG. 21 is a bottom view of the annular holder;

FIG. 22 is a front elevational view of the annular holder;

FIG. 23 is a cross-sectional view taken along line A--A of FIG. 21;

FIG. 24 is a cross-sectional view taken along line A--A of FIG. 20;

FIG. 25 is a cross-sectional view taken along line B--B of FIG. 21;

FIGS. 26, 27 and 28 are plan, front elevational and side elevationalviews of a driven roller encoder block;

FIG. 29 is a fragmentary enlarged cross-sectional view of the drivenroller encoder block;

FIGS. 30, 31 and 32 are front elevational and side elevational views ofan encoder case;

FIG. 33 is an exploded perspective view of a slider support and aslider;

FIG. 34 is a side elevational view of a slider support and sliderassembly;

FIG. 35 is a plan view of a pattern base plate;

FIG. 36 is an exploded perspective view of a contact roller, a supportshaft, a roller support, and a spring;

FIGS. 37, 38 and 39 are plan, side elevational and rear views of theroller support;

FIG. 40 is a fragmentary vertical cross-sectional view of the contactroller, the roller support, and the spring as arranged in a rollerholder;

FIG. 41 is a front elevational view, partly in cross-section, of theroller support engaged in the roller holder;

FIG. 42 is a fragmentary cross-sectional view of a construction forclamping a bearing;

FIG. 43 is a fragmentary cross-sectional view of a construction forclamping a tubular member;

FIG. 44 is a fragmentary cross-sectional view of a construction forsupporting bearings;

FIG. 45 is a plan view of the lower case with the annular holderattached and a printed-circuit board removed;

FIG. 46 is a plan view of the lower case with the annular holder and aprinted-circuit board attached;

FIG. 47 is a plan view of the printed-circuit board with switchesattached and a switch lever detached;

FIG. 48 is a vertical cross-sectional of a switch lever;

FIG. 49 is a bottom view of the switch lever;

FIG. 50 is a cross-sectional view of the switch lever mounted on theprinted-circuit board;

FIG. 51 is a cross-sectional view of the switch lever as it is operatedupon;

FIG. 52 is a side elevational view, partly in cross section, of arotation detector means according to another embodiment;

FIG. 53 is a plan view of a ball, driven rollers, and a contact rollerwhich are arranged in position;

FIGS. 54, 55 and 56 are plan, vertical cross-sectional, and frontelevational views of a movement limiting member;

FIG. 57 is a fragmentary plan view of the movement limiting member asplaced on the lower case; and

FIG. 58 is a cross-sectional view taken along line A--A of FIG. 57.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows in perspective a graphic display apparatus incorporatingtherein an X-Y input device according to the present invention.

The graphic display apparatus illustrated in FIG. 1 comprises a displayunit 2 mounted on a table 1 and having a screen, a controller, and adata channel, an input device 3 having function keys, and an X-Y inputdevice 4 according to the present invention. The X-Y input device 4 isoperated by the operator on a sheet 5 placed on the table 1 to move acursor 7 to any desired position on a screen 6 of the display unit 2.

The construction and principles of operation of the X-Y input device 4will be described with reference to FIGS. 2 through 5.

The X-Y input device 4 has a casing 8 composed of a lower case 9 and anupper case 10, the lower and upper cases 9, 10 being molded of ABSresin, for example. The lower case 9 and the upper case 10 have steppedperipheral joints held in engagement with each other to prevent dust,water and other foreign matter from entering into the casing 8 throughthe joints.

The upper case 10 is of a size which can be held by one hand of theoperator. The upper case 10, includes an upper wall 11, having slots 14defined therethrough in the longitudinal direction of the upper case 10.The control ends of rectangular switch levers 13 are inserted in theslots 14 from within the upper case 10 and partly project from the upperwall 11.

As described later on, pushbutton switches are disposed respectivelybelow the switch levers 13. The pushbutton switches serve not only asswitches for the input device 4 itself, but to delete a portion of adisplayed pattern immediately above or below the cursor 7, move such adisplayed pattern portion to another location, or effect other varioussignal processing such as switching or control on the display unit 2.The display unit 2 and the input device 4 is connected to each other bya cable 15 and an attachment plug 16.

FIG. 6 is a plan view of the lower case 9. The lower case 9 has a bottomwall 17 around which there are a front wall 18, a rear wall 19, arighthand side wall 20, and a lefthand side wall 21 that are arrangedcontiguously and erected upwardly. The bottom wall 17 has small throughholes 22a, 22b near corners between the front wall 18 and the righthandside wall 20 and between the front wall 18 and the lefthand side wall21, and a small through hole 22c near a central portion of the rear wall19. The small holes 22a-22c are positioned such that an isoscelestriangle will be drawn by connecting the centers of the small holes22a-22c.

FIG. 7 is a cross-sectional view taken along line A--A of FIG. 6. Eachof the small holes 22a-22c has an annular tapered surface 23 flaringupwardly. A tubular body 25 is integrally formed around an upper openedge of the tapered surface 23, leaving an annular flat surface 24. Arow of three studs 26 project from the bottom wall 17 and are spaced atintervals, the studs 26 being spaced rearwardly from the small holes22a, 22b by a certain distance. The studs 26 serve to support and attacha printed-circuit board (described later on).

The bottom wall 17 has a substantially circular opening 27 having adiameter slightly larger than that of a ball (described later on) forallowing the ball to be placed in and out of the casing, the opening 27being positioned immediately in front of the small hole 22c. FIG. 8 is across-sectional view taken along line B--B of FIG. 6 and FIG. 9 is across-sectional view taken along line C--C of FIG. 6. As shown in FIGS.6 and 9, the opening 27 has a peripheral edge including an upward step28 of a prescribed width having an upward flat engaging portion and adownward step 29 having a downward flat engaging portion, the downwardstep 29 extending the full peripheral edge of the opening 27 except theupward step 28. A radially outward recess 43 is defined adjacent to thedownward step 29 in diametrically opposite relation to the upward step28. The downward step 29 has a hexagonal hole 31 positioned above therecess 43 for receiving a small nut, the hexagonal hole 31 communicatingwith the recess 43 through a screw insertion hole 30. The bottom wall 17includes a peripheral wall 32 extending around the peripheral edge ofthe opening 27, the upward step 28, and the hexagonal hole 31.

Arcuate projections 34a, 34b having upper arcuate bearing surfaces 33are integrally formed with the peripheral wall 32 on its portion facingthe front wall 18, the arcuate projections 34a, 34b being spaced fromeach other. FIG. 11 is a cross-sectional view taken along line E--E ofFIG. 6. As shown in FIG. 11, stiffener ribs 35 are integrally formedwith the respective arcuate projections 34a, 34b at their lower ends.The bearing surface 33 of the arcuate projection 34a has a curvatureslightly smaller than that of the bearing surface 33 of the arcuateprojection 34b. As illustrated in FIG. 6, arcuate projections 36a, 36bare also integrally formed with the peripheral wall 32 with the upwardstep 28 interposed therebetween, the arcuate projections 36a, 36b beingspaced from each other. Like the arcuate projections 34a, 34b, thearcuate projections 36a, 36b have upper arcuate bearing surfaces 37 andintegral stiffener ribs 38 at their lower ends. The bearing surface 37of the arcuate projection 36a has a curvature slightly smaller than thatof the bearing surface 37 of the arcuate projection 36b.

FIG. 12 is a cross-sectional view taken along line F--F of FIG. 6. Asshown in FIGS. 12 and 6, two straight ridges 39, 39 extend parallel toeach other at a spaced interval in a direction from the corner betweenthe rear side wall 19 and the lefthand side wall 21 toward theperipheral wall 32, the ridges 39, 39 having ends integral with theperipheral wall 32. Two screw insertion holes 40, 40 are definedadjacent to the front wall 18, and one screw insertion hole 40 isdefined adjacent to the rear wall 19, these screw insertion holes 40serving to couple the lower and upper cases 9, 10 with screws. Two screwholes 41 shown in FIG. 6 serve to attach an annular holder (describedlater on) to an upper surface of the lower case 9.

FIGS. 13 through 16 illustrate a ring-shaped cover 42 to be attached toa lower surface of the lower case 9. The ring-shaped cover 42 has anoutside diameter which is substantially the same as the inside diameterof the downward step 29 of the lower case 9. The ring-shaped cover 42has a tongue 44 projecting from an outer peripheral portion thereof forbeing placed on the upward step 28, and an attachment 45 disposed indiametrically opposite relation to the tongue 44 for being fitted intothe recess 43, the attachment 45 having a screw insertion hole 46. Thering-shaped cover 46 has a central circular opening 47 having a diameterwhich is considerably smaller than the diameter of the ball. Thecircular opening 47 has an annular tapered surface 48 flaring upwardly.

For attaching the ring-shaped cover 42 to the lower case 9, the tongue44 is inserted from the lower surface of the lower case 9 into theopening 27 until the tongue 44 is placed on the upward step 28. Thering-shaped cover 42 is bodily fitted below the downward step 29. Asmall nut 49 (FIG. 17) is placed into the hexagonal hole 31 in the lowercase 9, and a screw 50 (FIG. 4) is threadedly inserted from thering-shaped cover 42. The ring-shaped cover 42 is now fixed to the lowercase 9 by engagement between the upward step 28 and the tongue 44 andthe screw 50A. The opening 27 in the lower case 9 is covered by thering-shaped cover 42, as shown in FIG. 17.

FIGS. 18 and 19 show in cross section a support ball 50 and a supportleg 51. FIG. 18 illustrates the support ball 50 and the support leg 51which are placed over each of the small holes 22a, 22b in the lower case9, and FIG. 19 illustrates the support ball 50 and the support leg 51which are placed over the small hole 22c in the lower case 9.

FIG. 18 will first be described. The support ball 50 which is made ofsteel and has a diameter greater than that of the small hole 22a (22b)is placed on the tapered surface 23 of the lower case 9. The supportball 50 has a portion projecting downwardly out of the small hole 22a(22b). The support leg 51 made of polyacetal is erected above thesupport ball 50. The support leg 51 has a cup-shaped portion 52 in whichthe support ball 50 is rotatably supported and which has an outsidediameter equal to or slightly larger than the inside diameter of thetubular body 25 of the lower case 9. The support leg 51 also has a post53 extending upwardly from the cup-shaped portion 52. and having anupper smaller-diameter end portion 54 to provide an engagement step 55at a lower end of the smaller-diameter end portion 54. Thesmaller-diameter end portion 54 is inserted into an engagement aperturedefined in a printed-circuit board 56. The printed-circuit board 56 isthus supported by the support leg 51. The support leg 51 as it engagesthe printed-circuit board 56 is prevented from being turned down afterassembly.

For assembly, the support ball 50, the support leg 51, and theprinted-circuit board 56 are successively placed on the lower case 9 inthe order named. If the support leg 51 were turned down, installation ofthe printed-circuit board 56 would not be possible. To cope with this,the tubular body 25 is provided around each small hole 22 in the lowercase 9 for contact with the cup-shaped portion 52 of each support leg 51to thereby prevent the support leg 51 from falling down at the time ofassembly. As shown, the support ball 50 is rotatably disposed in thecup-shaped portion 52. The support let 51 (cup-shaped portion 52) servesto prevent the support ball 50 from moving upwardly, with a portion ofthe support ball 50 projecting a given distance from the lower surfaceof the lower case 9 at all times.

The arrangement of FIG. 19 is different from the support structure withthe support leg 51. More specifically, an annular holder 57 has avertical through hole 58 in which the support leg 51 is inserted.Therefore, the support leg 51 is supported by the annular holder 57. Thesupport ball 50 and the support leg 51 are of the same configuration asthat shown in FIG. 18, and will not be described in further detail.

FIG. 20 is a plan view of the annular holder 57, FIG. 21 a bottom viewof the annular holder 57, and FIG. 22 a front elevational view of theannular holder 57. The annular holder 57 is molded ofpolybutyleneterephthalate, for example, and has a through opening 60 ofa size greater than the diameter of the ball, which is designated at 59.As shown in FIGS. 20 and 21, the annular holder 57 is composed of afirst driven roller holder section 61 for holding and positioning onedriven roller, a second driven roller holder section 62 for holding andpositioning another driven roller, and a roller holder section 63 forholding and positioning a frictional force imposing roller. The firstand second driven roller holder sections 61, 62 are arranged such thattheir longitudinal directions extend perpendicularly to each other. Theroller holder section 63 is disposed in spaced and confronting relationto the first and second driven roller holder sections 61, 62. The firstand second driven roller holder sections 61, 62 and the roller holdersection 63 are integrally molded in an annular shape by connectors 64.

Prior to describing the configuration of the driven roller holdersections 61, 62, a driven roller encoder block 65 to be fitted and heldthereby will first be described. FIGS. 26 through 29 are illustrative ofsuch a driven roller encoder block 65, FIG. 26 being a plan view, FIG.27 a front elevational view, FIG. 28 a righthand side elevational view,and FIG. 29 a fragmentary enlarged cross-sectional view.

The driven roller encoder block 65 is composed of a driven roller 66 andan encoder 67 which are integrally interconnected and will be handled asone block when assembled into the annular holder 57.

The drive roller 66 comprises a rotatable shaft 68, a roller section 69integrally formed with the rotatable shaft 68 at a substantially centralposition, and bearings 70a, 70b mounted on opposite ends of therotatable shaft 68.

The encoder 67 comprises an encoder case 71, a slider support 72connected to one end of the rotatable shaft 68. for rotation with thedriven roller 66, a slider 73 attached to the slider support 72, apattern base plate 74 positioned by the encoder case 71 in confrontingrelation to the slider 73, and an attachment plate 75 securely attachingthe pattern base plate 74 to the encoder case 71.

FIGS. 30 through 32 show the encoder case 71, FIG. 30 being a frontelevational view, FIG. 31 a lefthand side elevational view, and FIG. 32a righthand side elevational view. As illustrated in FIG. 32, theencoder case 71 comprises a rear wall 77, an upper wall 78, a lower wall79, and a lefthand side wall 80, with a righthand side being open almostentirely.

Each of the front wall 76 and the rear wall 77 has two upper and lowerengagement grooves 82 in which bent arms 81 (FIG. 27) of the attachmentplate 75 are fitted. As shown in FIG. 31, the engagement grooves 82extend partly into the lefthand side wall 80. Between the upper andlower engagement grooves 82, there are engagement fingers 83 extendingtoward the righthand side, with the engagement finger 83 on the frontwall 76 being positioned in opposite relation to the engagement finger83 on the rear wall 77.

The lefthand side wall 80 has a central integral cylindrical member 84extending toward the driven roller 66, and horizontal directionalprojections 85 are provided in front and rear positions in the vicinityof the opening in the cylindrical member 84. As illustrated in FIG. 32,the righthand ends of the front wall 76, the rear wall 77, the upperwall 78, and lower wall 79 have a noncircular annular step 86 having thesame shape as the outer profile of the pattern base plate 74. A housingrecess 107 is formed one step below the annular step 86.

As illustrate in FIG. 29, one end of the rotatable shaft 68 has asmaller-diameter portion 87 providing an engagement step 88 at an endthereof. The smaller-diameter portion 87 extends through an inner ring89 of a bearing 70b which comprises a ball bearing, and is force-fittedin a central hole 90 in the slider support 72. The bearing 70b has anouter ring 91 is force-fitted in the cylindrical member 84 of theencoder case 71. When the smaller-diameter portion 87 of the rotationalshaft 68 is force-fitted in the central hole 90 in the slider support72, the engagement step 88 is held against an end of the inner ring 89,which is then clamped between the slider support 72 and the engagementstep 88. The bearing 70b (inner ring 89) is now prevented by the encodercase 71 from being axially moved, so that the driven roller 66 will notbe axially displaced.

FIG. 33 is an exploded perspective view of the slider support 72 and theslider 73, and FIG. 34 is a righthand side elevational view of theslider support and slider assembly. The slider support 72 is molded ofpolybutylene terephthalate, for example, and has a central hole 90. Theslider support 72 has an attachment base 92 on a righthand side with twopositioning pins 93 projecting therefrom and spaced at a certaindistance. A C-shaped ridge 95 having a recess 94 is formed in thevicinity of the righthand open end of the central hole 90. The righthandside of the slider support 72 also has a substantially sectorial recess96.

The slider 73 has a substantially annular central portion 97 fitted overthe C-shaped rige 95 of the slider support 72 and includes a firstcontact end 98 formed by slitting the slider 73 and extending toward thecenter thereof. The slider 73 has attachment holes 99 at positionscorresponding to the positioning pins 93 of the slider support 72, andan integral arm 100 extending along an area corresponding to the recess96 in the slider support 72. The arm 100 has on a distal end thereofsecond inner and outer contact ends 102 formed as parallel ridges.

The slider 73 can be positioned with respect to the slider support 72 byinserting the positioning pins 93 of the slider support 72 into theattachment holes 99 in the slider 73 and also fitting the C-shaped ridge94 into the annular central portion 97. The slider 73 can then be firmlyfixed to the slider support 72 against wobbling movement by thermallyfusing the heads of the positioning pins 93. With the slider 73 thusfixed to the slider support 72, the free end portion of the firstcontact end 98 of the slider 73 is positioned in confronting relation tothe recess 94 and the central hole 90, and the arm 100 and the secondinner and outer contact ends 101, 102 are positioned in confrontingrelation to the recess 96. Accordingly, the first contact end 98, thearm 100, and the second inner and outer contact ends 101, 102 will beelastically deformed freely without being disturbed.

FIG. 35 is a plan view of the pattern base plate 74. The pattern baseplate 74 has a central pattern portion 103, an inner peripheral patternportion 104 formed concentrically with the central pattern portion 103,and an outer peripheral pattern portion 104 formed concentrically withthe central pattern portion 103. The pattern portions 103, 104, 105 areconnected to respective terminals 106.

For assembly, the slider support 72 with the slider 73 mounted on oneside thereof is inserted into the housing recess 107 in the encoder case71. The bearing 70b is fitted over the smaller-diameter portion 87 ofthe rotatable shaft 68 in advance, and the smaller-diameter portion 87and the bearing 70b are forced into the encoder case 71 through thecylindrical member 84. The distal end of the smaller-diameter portion 87is force-fitted into the central hole 90 in the slider support 72, andthe bearing 70b is force-fitted into the cylindrical member 84. Now, thedriven roller 66 is prevented from being axially pulled out, and theslider support 72 (slider 73) is rotatably held in the housing recess107 in the encoder case 71 for rotation with the driven roller 66.

Then, the pattern base plate 74 is fitted in the annular step 86 in theencoder case 71 with the pattern portions 103, 104, 105 facing theslider 73. Since the annular step 86 is of the same noncircular shape asthat of the outer profile of the pattern base plate 74, the pattern baseplate 74 can be positioned with respect to the encoder case 71. Theinterval that the pattern base plate 74 is inserted into the encodercase 71, or the distance that the pattern base plate 74 can be pushed intoward the slider 73, is determined by the height of the annular step86. When the pattern base plate 74 is being inserted into the encodercase 71, it is inserted while slightly pushing apart the two engagementfingers 83 which will then tentatively lock the pattern base plate 74 inthe encoder case 71. With the pattern base plate 74 thus tentativelylocked in the encoder case 71, the pattern base plate 74 will not bedisplaced or dislodged while the attachment plate 75 is being installed,and hence the assembling operation can be effected easily.

After the pattern base plate 74 has tentatively been locked in theencoder case 71, the C-shaped attachment plate 75 is held against theouter surface of the pattern base plate 74, and the four bent arms 81 ofthe attachement plate 75 are fitted respectively into the engagementgrooves 82 in the front and rear walls 76, 77. Then, the distal ends ofthe bent arms 81 are bent into the engagement grooves 82 in the lefthandside wall 80 of the encoder case 71, as shown in FIG. 31. The patternbase plate 74 is now finally fastened firmly to the encoder case 71.

With the pattern base plate 74 thus fixed to the encoder case 71, thefirst contact end 98 of the slider 73 is resiliently held against thecentral pattern portion 103 on the pattern base plate 74, and the secondinner and outer contact ends 101, 102 are resiliently held against theinner and outer peripheral pattern portions 104, 105, respectively. Byinserting and fixing the pattern base plate 74 in the encoder case 71,the contact ends 98, 101, 102 are slightly deformed under pressure.However, the dimensions of the parts are designed such that when theyare completely assembled together, the point where the first contact end98 contacts the central pattern portion 103 and the center of thecentral pattern portion 103 will be aligned with the axis of the drivenroller 66.

The driven roller encoder block thus constructed and assembled isinserted into each of the driven roller holder sections 61, 62.

The configuration of the driven roller holder sections 61, 62 will nowbe described.

Each of the driven roller holder sections 61, 62 has a bearing fittingslot 108 (FIGS. 21 and 23) in which there will be fitted the bearing 70athat is not force-fitted in the encoder case 71. The driven rollerholder section also has a projection fitting slot 109 in which therewill be fitted the directional projections 85, 85 of the encoder case71, and a cylindrical member fitting slot 110 in which there will befitted the cylinderical member 84, the slots 109, 110 being spacedrespective distances from the bearing fitting slot 108. The rotatableshaft 68 and the roller section 69 are inserted between the bearingfitting slot 108 and the projecting fitting slot 109. There are formedclearance recesses 111, 112, 113 to prevent the rotatable shaft 68 andthe roller section 69 from contacting the driven roller holder section61, 62. The roller section 69 is inserted and positioned in the centralrecess 112. Two removal prevention fingers 114, 114 project inwardlyfrom a peripheral wall 115 and are spaced a distance which is slightlylarger than the width of the roller section 69 (FIG. 24).

As shown in FIG. 21, the bearing fitting slot 108, the projectionfitting slot 109, the cylindrical member fitting slot 110, and therecesses 111, 113 open downwardly.

For assembly, the two driven roller encoder blocks 65 are insertedrespectively into the driven roller holder sections 61, 62 so that thebearing 70a, rotatable shaft 68 and roller section 69, directionalprojection 85, and the cylindrical member 84 of the driven rollerencoder block 65 will be fitted respectively in the bearing fitting slot108, recesses 111, 112, 113, projection fitting slot 109, andcylindrical member fitting slot 110 in the driven roller holder section61 (62).

At this time, the rotatable shaft 68 is inserted while pushing theremoval prevention fingers 114 slightly outwardly. When the rotatableshaft 68 is inserted in position, the distal end of the removalprevention finger 114 is slightly spaced from the rotatable shaft 68 soas not to interfere with rotation of the driven roller 66. With theremoval prevention fingers 114 provided in the driven roller holdersections 61, 62, there will be no danger for the driven roller encoderblocks 65 to be accidentally dislodged from the driven rollder holdersections 61, 62 at later handling occasions. Therefore, the assembly canbe handled with ease.

As illustrated in FIGS. 20, 22 and 24, the peripheral wall 115 has onits upper portion a lead wire seat 116 on which a lead wire extendingfrom the encoder is seated.

The roller holder section 63 will be described with particular referenceto FIGS. 21 and 25, FIG. 25 being a cross-sectional view taken alongline B--B of FIG. 21.

The roller holder section 63 for holding the frictional force imposingroller comprises a case opening downwardly and having therein a housingspace 117 in which a roller support (described later on) will slidablybe accommodated. As shown in FIG. 21, stop walls 118 depends from a sideof the housing space 117 which confronts the through opening 60, and aroller projecting opening 119 is defined between the stop walls 118.

As shown in FIG. 25, two confronting removal prevention fingers 121depend from an upper wall 120 (shown as being in a lower position) ofthe roller holder section 63 and are spaced a certain distance from eachother.

A contact roller 122, a support shaft 123, a roller support 124, and aspring 125 which will be held by the roller holder section 63 will bedescribed with reference to FIGS. 36 through 39. FIG. 36 is an explodedperspective view of the contact roller 122, the support shaft 123, theroller support 124, and the spring 125, and FIGS. 37, 38 and 39 areplan, side elevational and rear elevational views of the roller support.

The contact roller 122 is molded of polyacetal mixed withpolytetrafluoroethylene and has a very low coefficient of friction. Thecontact roller 122 has a shaft insertion hole 126 slighly larger indiameter, than the support shaft 123. Accordingly, the contact roller122 can freely rotate on the support shaft 123.

The roller support 124 is molded of polyamide and has two semicircularbearings 127 defined in opposite ends of a front surface and openingforward for supporting the ends of the support shaft 123. The rollersupport 124 also has a roller housing recess 128 (FIG. 38) definedbetween the bearings 127 and extending rearward, with a partition 129disposed behind the recess 128. The partition 129 has a circular springseat recess 130 defined in a rear surface thereof and opening rearward.

As shown in FIG. 39, the roller support 124 has clearance recesses 131defined substantially entirely in an upper surface, a lower surface, andrighthand and lefthand side surfaces, except for four corners, thusproviding straight ridges 132 extending from front to rear ends alongthe corners.

The spring 125 comprises a coil spring having one end inserted in thespring seat recess 130 in the roller support 124 and an opposite endheld against a rear wall 133 (FIGS. 21 and 40) of the roller holdersection 63.

The roller support 124 with the contact roller 122, the support shaft123, and the spring 125 supported thereon is pushed into the housingspace 117 in the roller holder section 63. Ridges 132 of the rollersupport 124 push slightly outwardly the heads of the two removalprevention fingers 121 while riding over the same, and then engage theremoval prevention fingers 121 as shown in FIG. 41. Since the contactroller 122, the support shaft 123, and the roller support 124 aretentatively locked in the roller holder section 63 upon engagementbetween the ridges 132 and the removal prevention fingers 121, therewill be no risk for these parts from dropping off when the annularholder 57 is to be installed on the lower case 9. Therefore, theassembling procedure can be simplified.

The removal prevention fingers 121 and the ridges 132 engaging therewithare dimensioned such that after their engagement, the roller support 124can slide in the housing space 117. When the spring 125 is inserted inthe housing space 117, it is held under compression between the springseat recess 130 in the roller support 124 and the rear wall 133 of theroller holder section 63, and resiliently forces the roller support 124to urge the contact roller 122 and the support shaft 123 into the rollerprojecting opening 119 (see FIG. 21). The contact roller has an outerperipheral portion projecting inwardly from the roller projectingopening 129 under the resiliency of the spring 125. The ends of thesupport shaft 123 are held against inner surfaces of the stop walls 118under the resiliency of the spring 125. With the ends of the supportshaft 123 held against the stop walls 118, the contact roller 122 andthe support shaft 123 are prevented from being dislodged. When the ball59 is inserted, as shown in FIG. 40, the contact roller 122 is slightlyretracted against the resilient force of the spring 125, so that thesupport shaft 123 is slightly spaced from the stop walls 118. Theresilient force from the spring 125 now acts on the ball 59 through theroller support 124, the support shaft 123, and the contact roller 122.

As described above, one of the two driven roller encoder blocks 65 isinserted and tentatively locked in the first driven roller holdersection 61, the other driven roller encoder block 65 is inserted andtentatively locked in the second driven roller holder section 62, andthe contact roller 122, the support shaft 123, the roller support 124,and the spring 125 are inserted and tentatively locked in the rollerholder section 63. The annular holder 57 thus assembled is mounted onthe lower case 9 with the openings in which the parts inserted beinglocated downwardly.

As shown in FIG. 19, the support ball 50 and the support leg 51 aredisposed above the small hole 22 in the lower case 9, and the supportleg 51 is inserted through the hole 58 (FIGS. 20 and 21) defined in theannular holder 57. The annular holder 57 is placed over the lower case 9with two screw insertion holes 134 (FIGS. 20 and 21) defined in theannular holder 57 being aligned with the screw holes 41 (FIG. 6) in thelower case 9. Then, the annular holder 57 is screwed to the lower case 9as shown in FIG. 45.

By thus installing the annular holder 57 on the lower case 9, thebearing 70a is sandwiched between the arcuate projection 34b (36b)projecting from the lower case 9 and the bearing fitting slot 108, asshown in FIGS. 42 and 44. As shown in FIGS. 43 and 44, the other bearing70b is sandwiched between the arcuate projection 34a (36a) projectingfrom the lower case 9 and the cylindrical member fitting slot 110, withthe cylindrical member 84 of the encoder case 71 being interposed. Sincethe bearing fitting slot 108 and the cylindrical member fitting slot 110are integrally formed in the driven roller holder section 61 (62), andthe arcuate projection 34a (36a) and the arcuate projection 34b (36b)are integrally formed with the lower case 9, the two driven rollers 66are properly oriented.

Although not shown, by attaching the annular holder 57 to the lower case9, the lower wall 79 of the encoder case 71 is held against the bottomwall 17 of the lower case 9 to prevent the encoder case 71 from beingturned. The annular holder 57 as thus mounted on the lower case 9 isillustrated in FIG. 45.

FIG. 47 is a plan view of the printed-circuit board 56 with pushbuttonswitches 135 mounted thereon. The pushbutton switches 135 are installedon the printed-circuit board 56 at predetermined positions thereon. Theprinted-circuit board 56 has an electrically conductive pattern 137connecting a plurality of lead wires 136 coupled to the encoders 67 tothe cable 15 through the pushbutton switches 135. The switch lever 13disposed over each of the pushbutton switches 135 is illustrated inFIGS. 48 and 49.

The switch lever 13 is composed, of a rectangular control end 14, aplurality of resilient members 138 projecting from a lower surface ofthe control end 14 near one end thereof for resiliently fitting over thehead of the pushtubbon switch 135, and a support leg 139 projecting fromthe lower surface of the cotnrol end 14 near the other end thereof. Asshown in FIG. 50, with the switch lever 13 fitted over the head of thepushbutton switch 135, the lower end of the leg 139 is positioned inconfronting relation to a portion of the printed-circuit board 56. Asillustrated in FIG. 47, there is no printed pattern 137 on bearingportions 140 facing the support legs 139.

As described above, the control end 14 of each of the switch levers 13is exposed through one of the holes 12 in the upper case 10. When thecontrol end 14 is depressed, the support leg 128 of the switch lever 13is brought into contact with the printed-circuit board 56, as shown inFIG. 51. Then, the lower end of the support leg 139 serves as a fulcrumfor allowing the switch lever 13 to turn toward the pushbutton switch135 for actuating the latter.

As shown in FIG. 47, the printed-circuit board 56 has two engagementholes 141 in which the smaller-diameter portions 54 of the support legs51 are fitted, and two engagement holes 142 in which the heads of thestuds 26 on the lower case 9 are fitted.

After the annular holder 57 has been mounted on the lower case 9 in themanner described above, the support balls 50 and the support legs 51 areplaced over the front small holes 22a, 22b in the lower case 9. As shownin FIG. 18, the support legs 51 can be vertically fixed by the tubularbodies 25 without the danger of falling down. Therefore, thesmaller-diameter portions 54 of the support legs 51 can easily beinserted into the engagement holes 141 in the printed-circuit board 56.At the same time that the smaller-diameter portions 54 are inserted intne engagmeent holes 141, the heads of the studs 26 (FIG. 6) areinserted into engagement holes 142 defined in the printed-circuit board56. Thereafer, the printed-circuit board 56 is screwed to the studs 26,as depicted in FIG. 46.

After the printed-circuit board 56 is thus fastened in position, theswitch levers 13 are fitted over the pushbutton switches 135, and theupper case 10 is placed over and screwed to the lower case 9, thuscompleting the casing 8.

The ball 59 has not yet been installed in place. The ball 59 is theninserted into the casing 8 through the opening 27 defined in the lowercase 9. Since the two driven rollers 66 disposed in mutuallyperpendicular relation (X - Y directions) are supported respectively bythe roller holders 21, 22, only the contact roller 122 is retractedagainst the resiliency of the spring 125 upon insertion of the ball 59into the casing 8. After the ball 59 has been inserted in position, theball 59 is clamped between the two driven rollers 66 and the contactroller 122 under the resiliency of the springs 125. Then, the opening 27is covered with the ring-shaped cover 42, which will be screwed to thelower case 9. The assembly of the input device is now completed.

While in the foregoing embodiment the encoders have been described asmeans for detecting the amount of rotation of the driven rollers, thepresent invention is not limited to such an arrangement. FIG. 52 shows arotation detector means according to another embodiment. A rotatabledisk 143 is concentrically attached to one end of the rotatable shaft 68of the driven roller 66, and has a plurality of reflectors 144 areattached to an outer peripheral surface of the disk 143 and spaced atequal intervals in the peripheral direction. A pair of light-emittingelement 145 and photodetector 146 is disposed in confronting relation tothe reflectors 144. A beam of light emitted from the light-emittingelement 145 is reflected by the reflectors 144. Intermittent lightreflections are detected by the photodetector 146 and then counted fordetecting the amount of rotation of the driven roller 66.

As an alternative, a number of light transmitting slits may be definedin a rotatable disk peripherally along an outer peripheral portionthereof, and a light-emitting element and a photodetector may bedisposed one on each side of the rotatable disk.

FIG. 53 shows the ball 59, the two driven rollers 66, and the contactroller 122 which are arranged in an assembled position. The two drivenrollers 66 are held and positioned by the first and second driven rollerholder sections 61, 62, so that the axes of the two driven rollers 66extend perpendicularly with each other.

The contact roller 122 is held in contact with the ball 59 andpositioned across the ball 59 in opposite relation to the two drivenrollers 66. The contact roller 122 serves to transmit power reliablybetween the ball 59 and the driven rollers 66. The contact roller 122 isfreely rotatable with rotation of the ball 59 and resiliently urges theball 59 against the driven rollers 66.

The contact roller 122 is disposed with respect to the ball 59 and thedriven rollers 66 such that a straight line Q passing through the pointP of contact between the ball 59 and the contact roller 122 and thecenter O of rotation of the ball 59 intersects the axes of the driverollers 66 at about 45 degrees (θ₁, θ₂) for equalizing the pressure ofcontact between the ball 59 and one of the driven rollers 66 to thepressure of contact between the ball 59 and the other driven roller 66.Therefore, the angles θ₁, θ₂ are designed to be equal to each other.

The two driven rollers 66 are individually rotated by the rotation ofthe ball 59, and directions and angles of rotation of the driven rollers66 are detected by the rotation detector means such as the encoders 67associated respectively with the driven rollers 66. The state ofrotation of the ball 59 can therefore be detected as components in theX- and Y-axis directions.

The input device 4 is placed on a given base 147 in the manner shown inFIGS. 3 through 5. The three support balls 50 have portions projectingdownwardly through the small holes 22a, 22b, 22c for bearing thecombined weight of the casing 8, the printed-circuit board 56, theannular holder 57, the two driven roller encoder blocks 65, and thecontact roller 122 through the support legs 51. A portion of the ball 59also projects downwardlythrough the opening 47 in the ring-shaped cover42. The ball 59 is pressed against the base 147 chiefly under its ownweight.

If there is water, ink, oil, or dust on the base 147, then such foreignmatter tends to get stuck to the surface of the ball 59 while the inputdevice 4 is in use on the base 147. Such accumulation of unwantedforeign matter on the ball 59 would cause the driven rollers 66 to slipon the ball 59, with the result that no accurate transmission ofrotative power would be effected between the ball 59 and the drivenrollers 66, and the reliability of the input device 4 would be lowered.According to the present invention, the ring-shaped cover 42 isdetachably attached to the lower case 9 to allow the ball 59 to be takenout of the casing 8 periodically or as desired for cleaning.

Since the printed-circuit board 56 with the pushbutton switches 135 isnot disposed directly above the ball 59, but displaced laterally off theball 59, the entire height of the input device 4 is lowered, and hencethe input device 4 can be small in size and of a low profile.

FIGS. 54 through 58 illustrate a movement prevention member 145according to another embodiment for preventing the support ball 50 frommoving upwardly. The movement prevention member 145 has a lowercup-shaped portion 149 in which the support ball 50 is rotatablyaccommodated. Three abutment ribs 150 project radially outwardly from anouter peripheral surface of the cup-shaped portion 149 and areperipherally spaced at intervals. As shown in FIG. 58, the rib 150 has avertical end surface held against an inner surface of the tubular body25 projecting from the lower case 9.

The movement prevention member 145 includes an insertion end 151 abovethe cup-shaped portion 149. The insertion end 151 will be inserted intoa slot or a recess defined in the annular holder 57 to prevent themovement prevention member 148 from being raised.

An arm 152 extends horizontally in a radially outward direction from anouter peripheral portion of the cup-shaped portion 149 which is devoidof the abutment rib 150. An annular member 153 is integrally formed witha distal end of the arm 152.

FIGS. 57 and 38 show the movement prevention member 128 placed on thelower case 9. As illustrated in FIG. 58, the support ball 50 of steel isplaced over the small hole 22 in the lower case 9, and the movementprevention member 148 is disposed over the support ball 50. A steppedsupport pin 154 projects upwardly from the lower case 9 in the vicinityof the small hole 22 and has a head inserted in a hole in the annularmember 153. The movement prevention member 148 is positioned andprevented from being displaced and turned down through engagementbetween the annular member 153 and the support pin 154 and abutment ofthe abutment ribs 150 against the tubular body 25.

Although certain preferred embodiments have been shown and described, itshould be understood that many changes and modifications may be madetherein without departing from the scope of the appended claims.

What is claimed is:
 1. An X-Y input device comprising a rotatable ball,a first driven roller held in contact with said rotatable ball androtatable in response to rotation of said rotatable ball, a seconddriven roller held in contact with said rotatable ball and rotatable inresponse to rotation of said rotatable ball, said second driven rollerhaving an axis of rotation extending substantially perpendicularly tothat of said first driven roller, first rotation detector means fordetecting an amount of rotation of said first driven roller, and secondrotation detector means for detecting an amount of rotation of saidsecond driven roller, each of said rotation detector means comprising apattern base plate including a central pattern and a peripheral patternconcentric with said central pattern, a slider having a first contactend held in slidable contact with said central pattern and a secondcontact end held in slidable contact with said peripheral pattern, and aslider support supporting said slider and connected to each of saiddriven rollers for rotation therewith, said first contact end of saidslider being held in contact with said central pattern at a pointaligned with a central axis of rotation of said driven roller.
 2. An X-Yinput device according to claim 1, wherein said first contact end isformed from a central portion of said slider so that it projects from acenter thereof, said first contact end being resiliently pressed againstsaid central pattern.
 3. An X-Y input device comprising a rotatableball, a first driven roller held in contact with said rotatable ball androtatable in response to rotation of said rotatable ball, a seconddriven roller held in contact with said rotatable ball and rotatable inresponse to rotation of said rotatable ball, said second driven rollerhaving an axis of rotation extending substantially perpendicularly tothat of said first driven roller, first rotation detector means fordetecting an amount of rotation of said first driven roller, and secondrotation detector means for detecting an amount of rotation of saidsecond driven roller, each of said rotation detector means comprising apattern base plate including a central pattern and a peripheral patternconcentric with said central pattern, a slider having a first contactend held in slidable contact with said central pattern and a secondcontact end held in slidable contact with said peripheral pattern, and aslider support supporting said slider and connected to each of saiddriven rollers, for rotation therewith, said central pattern of saidpattern base plate having a center aligned with a central axis ofrotation of said driven roller.
 4. An X-Y input device according toclaim 2, wherein said first contact end is formed from a central portionof said slider so that it projects from a center thereof, said firstcontact end being resiliently pressed against said central pattern.